Image display devices such as cathode ray tube (CRT) displays, liquid crystal displays (LCDs), plasma displays (PDPs), electroluminescence displays (ELDs), field emission displays (FEDs), touch panels, electronic paper, and tablet PCs have, on their outermost surface, an optical layered body formed from a functional layer that has various properties including an anti-glare property, an anti-reflection property, and an antistatic property.
Conventionally known optical layered bodies include ones in each of which a hard coat layer is formed on a transparent substrate that is made of a material such as triacetyl cellulose. The hard coat layer is typically formed by applying a coating liquid containing polyfunctional monomers to a transparent substrate; and curing the dried coating film by UV irradiation, as described in, for example, Patent Literatures 1 and 2.
Those optical layered bodies may be rolled or stacked on another optical layered body in the production process. The optical layered bodies, however, easily stick to each other because their hard coat layers are made of a plastic material such as an acrylic resin. Because of this nature, the optical layered bodies are not easily separated from each other when rolled or subjected to another treatment in the production process, i.e., they exhibit a phenomenon called blocking. Blocking may change the shape of the optical layered bodies or leave trace of sticking on the optical layered bodies, and thus causes a problem of a productivity decrease.
Also, an optical layered body may have a protective film on its hard coat layer, and may be irradiated with strong ultraviolet light through the protective film when processed to form a polarizer. Some protective films include a portion with markings such as process-control lot numbers. Such a portion with markings changes the amount of UV light reaching the hard coat layer, compared to portions without markings. The different amounts of UV light cause unreacted monomers remaining in the hard coat layer to be reacted differently to lead to different levels of cross-linked curing shrinkage between the portion with markings and the portions without markings. The different levels of cross-linked curing shrinkage result in a problem that the marking leaves trace of itself on the surface of the hard coat layer.